1. Field of the Invention
The invention relates to a containment of a nuclear power station having a device for igniting hydrogen contained in a hydrogen/air mixture.
In the ever so unlikely event of accident situations in which an oxidation of zirconium can occur, for example due to a core heat-up, for precautionary reasons it is expected that hydrogen gas can be formed in a nuclear power station and released inside the containment surrounding the reactor core. An explosive gas mixture, in particular a hydrogen/air mixture, can thereby be produced inside the containment.
Various devices or methods are discussed for the purpose of preventing a formation of such an explosive gas mixture in the containment of a nuclear power station. Those include, for example, devices such as catalytic recombiners or catalytically and/or electrically operated ignition devices for igniting hydrogen. When hydrogen ignites, it reacts with oxygen present in the air in the containment to form water, and is thereby recombined. Such an ignition device is disclosed, for example, in German Published, Non-Prosecuted Patent Application DE 41 25 085 A1, corresponding to U.S. Pat. Nos. 5,492,686 and 5,592,521. Alternatively, consideration is also given to methods for permanently or subsequently inerting the containment.
In a conventionally used electrically driven ignition device such as is described, for example, in German Patent DE 30 04 677 C, a multiplicity of igniters or spark plugs is disposed inside the containment of the nuclear power station. Each of those igniters is suitable for igniting the hydrogen of the hydrogen/air mixture in its immediate environment, and thus for recombining it. The action of such an igniter is therefore narrowly limited locally. It is therefore impossible to keep the hydrogen concentration inside the entire containment at a uniformly low level below the prescribed limiting value, by using such igniters.